赤膊上阵 — “To strip to the waist and go into battle”

At the end of the Eastern Han Dynasty, the imperial court was corrupt, and warlords carved up territories, constantly warring with each other. Ma Teng, a warlord who controlled Liangzhou, was killed by Cao Cao.

Ma Chao, Ma Teng's son, sought revenge for his father and allied with Han Sui, the Prefect of Xiliang, mobilizing hundreds of thousands of troops to attack Cao Cao. The two armies confronted each other near Weikou.

The next day, both armies emerged from their camps and arrayed their formations. Ma Chao, holding his spear and spurring his horse, fought fiercely with Cao Cao's brave general, Xu Chu. They battled for over a hundred rounds without a clear victor. As their warhorses grew weary and could no longer sustain the fight, they each returned to their respective armies, changed horses, and then re-emerged to fight another hundred rounds, still without a decisive outcome.

Xu Chu, spurred by the heat of battle, galloped back to his formation, removed his armor, revealing his prominent muscles, and, stripped to the waist, mounted his horse with a saber to face Ma Chao in a decisive battle. The officers and soldiers on both sides were greatly astonished. They fought for another thirty rounds. Xu Chu forcefully raised his blade to strike at Ma Chao, who dodged it and thrust his spear towards Xu Chu's heart. Xu Chu threw away his saber and clamped down hard on Ma Chao's spear. The two then wrestled for the spear on horseback. With his great strength, Xu Chu snapped the spear shaft with a 'crack', and both, each holding half, continued to fight wildly on their horses.

Following this, the two armies engaged in a chaotic battle. Cao Cao's forces suffered heavy losses and retreated to their camp, refusing to come out. Ma Chao returned to Weikou and said to Han Sui, 'In the heat of battle, I have never seen anyone as fearless as Xu Chu. He truly is a 'Tiger Berserker'!'